Isradipine belongs to the dihydropyridine (DHP) class of calcium channel blockers (CCBs), the most widely used class of CCBs. It is structurally related to felodipine, nifedipine, and nimodipine and is the most potent calcium-channel blocking agent of the DHP class. Isradipine binds to calcium channels with high affinity and specificity and inhibits calcium flux into cardiac and arterial smooth muscle cells. It exhibits greater selectivity towards arterial smooth muscle cells owing to alternative splicing of the alpha-1 subunit of the channel and increased prevalence of inactive channels in smooth muscle cells. Isradipine may be used to treat mild to moderate essential hypertension.
The T-value in the score for hazard refers to acute/chronic toxicity. Underlying data for P, B and T comes from Fass, see below. Fass environmental information for Lomir SRO (isradipine), (downloaded 2018-06-27) Hazard Persistence: "7-12 % degradation in 28 days, not readily biodegradable (OECD 301B). The phrase “Isradipine is potentially persistent” is thus chosen." Bioaccumulation: Log Kow = 4.1 (OECD 107). Acute toxicity: There is data for 3 trophic levels, lowest for fish (Oncorhynchus mykiss, rainbow trout) LC50 96 h (mortality) 76 microg/L. Risk PEC/PNEC is based on sales data in Sweden in year 2015. PEC/PNEC = 0.0081 which gives the risk insignificant. PBT/vPvB assessment "Based on the available information, isradipine fulfills the screening criteria for a potential PBT substance. No definitive judgement on PBT can be made as only data for PBT screening are available, not for definitive PBT assessment."